The documentation <URL: http://www.haskell.org/ghc/docs/latest/set/finitemap.html > doesn't say whether fmToList et al are /defined/ to return a list in Ord order of the keys. I think it should. Jón -- Jón Fairbairn Jon.Fairbairn at cl.cam.ac.uk 31 Chalmers Road jf at cl.cam.ac.uk Cambridge CB1 3SZ +44 1223 570179 (after 14:00 only, please!)